Parenteral nutrition is a form of nutrition that is administered intravenously, bypassing the digestive system. It is used to provide essential nutrients to patients who are unable to obtain adequate nutrition through oral or enteral means. Parenteral nutrition is typically used in patients who have a condition that prevents them from being able to absorb nutrients from food, such as those with severe gastrointestinal disorders or those who have had surgery that has removed part of their digestive tract.